Caller identification (ID) service may be provided to users of mobile communication devices. Thus, when a first user receives a telephone call from a second user, the second user's identification information, such as the name and phone number of the second user, may be displayed on the first user's mobile communication device while a ringing signal is being played, or while the telephone call is being set up by the network and before the call is answered. The caller ID information for a telephone number may be obtained from a caller ID database, which may be available to providers of mobile communication services.